THURSDAY, Feb. 20, 2014 (HealthDay News) -- People in cold, northern regions of the world have more gut bacteria linked with obesity than those in warm, southern areas, researchers report.

The findings are from an analysis of gut bacteria in more than 1,000 people in Africa, Asia, Europe, North America and South America.

"People think obesity is a bad thing, but maybe in the past getting more fat and more energy from the diet might have been important to survival in cold places," study author Taichi Suzuki, a graduate student at the University of California, Berkeley, said in a university news release. "Our gut microbes today might be influenced by our ancestors."

The study appeared online this month in the journal Biology Letters.

One theory is that obesity-associated gut bacteria can extract more energy from food, said Suzuki, who added that the findings suggest that what is considered healthy gut bacteria might vary according to geographic region.

Study author Michael Worobey, an evolutionary biologist at the University of Arizona, said the finding is "pretty cool, but it is not clear why we are seeing the relationship we do with latitude."

"Maybe changes to your gut community of bacteria are important for allowing populations to adapt to different environmental conditions in lots of animals, including humans," Worobey said in the news release.